Whenever doing a close analysis or "close reading," it's good to choose a brief excerpt from the text rather than trying to range widely over many words. Here is a passage from Macbeth, chosen pretty much at random, which we can look at closely. It comes from Act I, Scene 3. In this passage, Macbeth is responding to the successful fulfillment of part of the witches’ prophecy concerning him:

Macbeth. [Aside]. Two truths are told, 240 As happy prologues to the swelling act Of the imperial theme.—I thank you, gentlemen. [Aside] This supernatural soliciting] Cannot be ill, cannot be good: if ill, Why hath it given me earnest of success, 245 Commencing in a truth? I am thane of Cawdor: If good, why do I yield to that suggestion Whose horrid image doth unfix my hair And make my seated heart knock at my ribs, Against the use of nature? Present fears 250 Are less than horrible imaginings: My thought, whose murder yet is but fantastical, Shakes so my single state of man that function Is smother'd in surmise, and nothing is But what is not. 255

Note how in this passage, Macbeth is already speaking in an aside, suggesting much about his character: that he has something to hide, that he is privately ambitious, and that he is a man full of thoughts but is not always willing to share his thoughts with others. Obviously, these asides already foreshadow much of his later secretive, devious behavior.

Meanwhile, his reference to the “imperial theme” emphasizes a major motif of the play: his later desire to be king and to monopolize power. The reference to “supernatural soliciting” also highlights a major theme of the play, and it is interesting that Macbeth uses the noun “soliciting,” implying that he is not yet won over to a full commitment to evil and implying, too, that he does not (and will not) accept full personal responsibility for his own ambitions.

The phrase “Cannot be ill, cannot be good” typifies Macbeth’s tendency to vacillate, to see both sides to a degree that sometimes paralyzes him. His is a deeply divided mind (at least at first), and Shakespeare implies as much by using phrasing such as this. The fact that Macbeth then develops the implications of this phrase for the next several lines shows that he is capable of real thought, and it also raises some of the major ethical issues of the play.

When Macbeth refers to the unfixing of his hair and to his

. . . seated heart knock[ing] at [his] ribs,

Against the use of nature . . .

Shakespeare shows his gift for concocting vivid imagery while also anticipating, perhaps, the later knocking at the gates of the castle. Finally, this phrase also implies the theme of unnatural behavior that is pervasive in the play. Characteristically, the passage ends with more paradoxical language suggesting once more a divided mind: